Rational Cancer Treatment Combinations: An Urgent Clinical Need.

We are witnessing several revolutionary technological advances in cancer. These innovations have not only contributed to a growing understanding of the tumor and its microenvironment but also uncovered an increasing array of new therapeutic targets. For most advanced cancers, therapy resistance limits the benefit of single-agent therapies. Therefore, some 5,000 clinical trials are ongoing globally to probe the clinical benefit of new combination treatments. However, the possibilities to combine individual treatments dramatically outnumber the patients available to enroll in clinical trials. This comes at a potential cost of missed opportunities, clinical failure, avoidable toxicity, insufficient patient accrual, and financial loss. A solution may be to design combination therapies more rationally, which are informed by fundamental biological and mechanistic insight. We will discuss some successes and failures of current treatment combinations, as well as interesting emerging preclinical concepts that warrant clinical exploration.